This proposal is for continuing support of the pre-doctoral training grant in biology at the Massachusetts Institute of Technology (MIT). This training grant (in its 40th year) continues to be the most important source of support for graduate students studying biological science at MIT. The mission of this program is to train the next generation of biological/biomedical scientists, many of whom will be innovators and leaders in research and education. Specifically, in this training program we strive to educate our students: to understand the fundamental underlying principles of modern biology including genetics, biochemistry, cell biology, molecular biology and quantitative data analysis; to be ethical decision makers; to flexibly adapt to the rapidly changing modern biomedical sciences landscape; to become creative, effective, rigorous researchers; to become excellent communicators of science, and to become thoughtful teachers and mentors. We seek out, recruit and train talented students from majority, underrepresented minority, and disadvantaged populations, and help them initiate successful research careers. Trainees admitted to our program have outstanding undergraduate academic records and have demonstrated strong motivation to pursue research. A key feature of our program is an intensive, focused curriculum required of all first-semester students. Students work together in lecture and discussion-style courses taught by dedicated faculty to master a fundamental set of approaches that underpin all modern molecular biological science. The training program exposes students to the research interests of all faculty members in the Biology Department prior to the critical choice of a thesis lab and topic. Responsible conduct in research is taught in three phases, including an intense mini-course for 2nd year students. We aim to support 46 predoctoral students per year, primarily in their first and second years of training; the complete Ph.D. program takes trainees approximately 5.8 years to complete. Students' progress through the program is monitored in regular thesis committee meetings with faculty members, with oversight provided by the graduate committee. Our students perform research of outstanding quality, and most trainees go on to careers in biomedical research. Many of our former trainees are now leaders in their chosen fields.